Mr Sarkozy said that France and Germany were in favour of a financial transactions tax and they hoped it would be implemented in 2012.
US President Barack Obama was enthusiastic about commitments to greater currency flexibility.
"We welcome China's determination to increase the flexibility of the renminbi," he said.
"This is something we've been calling for for some time and it will be a critical step in boosting growth."
Mr Cameron said it was "essential for confidence and economic stability" that the IMF had the resources it needed, but reaffirmed that the UK would not contribute to any eurozone bailout.
German Chancellor Angela Merkel confirmed that no countries outside the eurozone had offered to contribute to the bailout fund.
The leaders released a final communique, which:
- Commits to move "more rapidly" towards greater exchange rate flexibility, without specifically mentioning China
- Agrees to support the IMF and give it more money if necessary
- Welcomes Italy's invitation to the IMF to monitor its economic reforms
- Calls on countries with strong public finances to take steps to boost domestic demand
- Welcomes the eurozone's plans to restore confidence and financial stability
- Sets up a task force on youth employment
David Cameron said
"Resourcing the IMF is not a substitute for the eurozone dealing with its own issues and problems”
The head of the IMF, Christine Lagarde, told the BBC that she had received a "commitment" from the leaders.
